The design of low-power CIFF structure second-order sigma-delta modulator

This paper presents the design and implementation of a low power sigma-delta modulator (SDM) with a standard 0.18-µm CMOS technology. A current optimization technique is utilized in proposed design to reduce the power of operational trans-conductance amplifier(OTA). Using a chain of Integrators with weighted feed-forward summation (CIFF) structure and optimized single-stage class-A OTA with positive feedback to minimize the power consumption, the second-order SDM achieves a SNR of 64dB that be able to process the signal form DC to 16 KHz. The power consumption is only 18.1 uW from a 1-V supply.